According to Holy Scripture the number of angels is very large (Dan. 7, 10: "thousand thousands and ten thousand times ten thousand"; Luke 2, 13 : "a multitude of the heavenly host"; Ps. 68, 17: "twenty thousand, even thousands of angels"). All these expressions are symbolical numbers, standing for uncounted thousands. How great is the goodness of God, who created so many holy ministers for the benefit of man!
That there are ranks, or orders, among the angels is clear from the special names given them in Scripture (Gen. 3, 24: cherubim; Is. 6, 2: seraphim; Col. 1, 16: thrones, dominions, principalities, powers; 1 Thess. 4, 16: archangel). Also among the evil angels there are greater and lesser spirits (Matt. 25, 41: "the devil and his angels"; Luke 11, 15. 18. 19 : "Beelzebub, the chief of the devils"). However, we can neither determine the number of the angels, nor can we describe the ranks, or orders, among them since Holy Scripture does not give us adequate information on this subject, nor does it always enumerate the angelic ranks in the same order (cp. Col. 1, 16 with Eph. 1, 21), so that we cannot tell which is the higher and which the lower. Gregory Nazianzen: Ordo angelorum notus est ei, qui ipsos ordinavit." Baier aptly remarks that, while the angels differ from one another with respect to rank, they do not differ from one another with respect to kind and nature (specie et essentia). In the appointment of ranks, or orders, among the angels we witness the wisdom of God, who is not "the author of confusion," 1 Cor. 14, 33.